Morphine, formerly also called morphia, is an opiate that is found naturally in opium, a dark brown resin produced by drying the latex of opium poppies. It is mainly used as an analgesic. There are numerous methods used to administer morphine: oral; sublingual; via inhalation; injection into a muscle, injection under the skin, or injection into the spinal cord area; transdermal; or via rectal suppository. It acts directly on the central nervous system (CNS) to induce analgesia and alter perception and emotional response to pain. Physical and psychological dependence and tolerance may develop with repeated administration. It can be taken for both acute pain and chronic pain and is frequently used for pain from myocardial infarction, kidney stones, and during labor. Its maximum effect is reached after about 20 minutes when administered intravenously and 60 minutes when administered by mouth, while the duration of its effect is 3–7 hours. Long-acting formulations of morphine are sold under the brand names MS Contin and Kadian, among others. Generic long-acting formulations are also available.
Tramadol, sold under the brand name Ultram among others, is an opioid pain medication and a serotonin–norepinephrine reuptake inhibitor (SNRI) used to treat moderately severe pain. When taken by mouth in an immediate-release formulation, the onset of pain relief usually begins within an hour. It is also available by injection. It is available in combination with paracetamol (acetaminophen).
Hydromorphone, also known as dihydromorphinone, and sold under the brand name Dilaudid among others, is a morphinan opioid used to treat moderate to severe pain. Typically, long-term use is only recommended for pain due to cancer. It may be used by mouth or by injection into a vein, muscle, or under the skin. Effects generally begin within half an hour and last for up to five hours. A 2016 Cochrane review found little difference in benefit between hydromorphone and other opioids for cancer pain.
Opioids are a class of drugs that derive from, or mimic, natural substances found in the opium poppy plant. Opioids work in the brain to produce a variety of effects, including pain relief. As a class of substances, they act on opioid receptors to produce morphine-like effects.
Dihydrocodeine is a semi-synthetic opioid analgesic prescribed for pain or severe dyspnea, or as an antitussive, either alone or compounded with paracetamol (acetaminophen) or aspirin. It was developed in Germany in 1908 and first marketed in 1911.
Ethylmorphine is an opioid analgesic and antitussive.
Morphine-6-glucuronide (M6G) is a major active metabolite of morphine. M6G is formed from morphine by the enzyme UGT2B7. It has analgesic effects more potent than morphine. M6G can accumulate to toxic levels in kidney failure.
Lefetamine (Santenol) is a drug which is a stimulant and also an analgesic with effects comparable to codeine.
Opioid-induced hyperalgesia (OIH) or opioid-induced abnormal pain sensitivity, also called paradoxical hyperalgesia, is an uncommon condition of generalized pain caused by the long-term use of high dosages of opioids such as morphine, oxycodone, and methadone. OIH is not necessarily confined to the original affected site. This means that if the person was originally taking opioids due to lower back pain, when OIH appears, the person may experience pain in the entire body, instead of just in the lower back. Over time, individuals taking opioids can also develop an increasing sensitivity to noxious stimuli, even evolving a painful response to previously non-noxious stimuli (allodynia). This means that if the person originally felt pain from twisting or from sitting too long, the person might now additionally experience pain from a light touch or from raindrops falling on the skin.
Zomepirac is an orally effective nonsteroidal anti-inflammatory drug (NSAID) that has antipyretic actions. It was developed by McNeil Pharmaceutical, approved by the FDA in 1980, and sold as the sodium salt zomepirac sodium, under the brand name Zomax. Due to its clinical effectiveness, it was preferred by doctors in many situations and obtained a large share of the analgesics market; however, it was subsequently withdrawn in March 1983 due to its tendency to cause serious anaphylaxis in a small, but unpredictable, subset of the patient population.
UGT2B7 (UDP-Glucuronosyltransferase-2B7) is a phase II metabolism isoenzyme found to be active in the liver, kidneys, epithelial cells of the lower gastrointestinal tract and also has been reported in the brain. In humans, UDP-Glucuronosyltransferase-2B7 is encoded by the UGT2B7 gene.
Codeine is an opiate and prodrug of morphine mainly used to treat pain, coughing, and diarrhea. It is also commonly used as a recreational drug. It is found naturally in the sap of the opium poppy, Papaver somniferum. It is typically used to treat mild to moderate degrees of pain. Greater benefit may occur when combined with paracetamol (acetaminophen) or a nonsteroidal anti-inflammatory drug (NSAID) such as aspirin or ibuprofen. Evidence does not support its use for acute cough suppression in children. In Europe, it is not recommended as a cough medicine in those under 12 years of age. It is generally taken by mouth. It typically starts working after half an hour, with maximum effect at two hours. Its effects last for about four to six hours. Codeine exhibits abuse potential similar to other opioid medications, including a risk of addiction and overdose.
Dezocine, sold under the brand name Dalgan, is an atypical opioid analgesic which is used in the treatment of pain. It is used by intravenous infusion and intramuscular injection.
Ciramadol (WY-15,705) is an opioid analgesic that was developed in the late 1970s and is related to phencyclidine, tramadol, tapentadol and venlafaxine. It is a mixed agonist-antagonist for the μ-opioid receptor with relatively low abuse potential and a ceiling on respiratory depression which makes it a relatively safe drug. It has a slightly higher potency and effectiveness as an analgesic than codeine, but is weaker than morphine. Other side effects include sedation and nausea but these are generally less severe than with other similar drugs.
Heterocodeine (6-methoxymorphine) is an opiate derivative, the 6-methyl ether of morphine, and a structural isomer of codeine; it is called "hetero-" because it is the reverse isomer of codeine. Heterocodeine was first synthesised in 1932 and first patented in 1935. It can be made from morphine by selective methylation. Codeine is the natural mono-methyl ether, but must be metabolized for activity. In contrast the semi-synthetic mono-methyl ether, heterocodeine is a direct agonist. The 6,7,8,14 tetradehydro 3,6 methyl di-ether of morphine is thebaine.
Propiram is a partial μ-opioid receptor agonist and weak μ antagonist analgesic from the ampromide family of drugs related to other drugs such as phenampromide and diampromide. It was invented in 1963 in the United Kingdom by Bayer but was not widely marketed, although it saw some limited clinical use, especially in dentistry. Propiram reached Phase III clinical trials in the United States and Canada.
An active metabolite, or pharmacologically active metabolite is a biologically active metabolite of a xenobiotic substance, such as a drug or environmental chemical. Active metabolites may produce therapeutic effects, as well as harmful effects.
An equianalgesic chart is a conversion chart that lists equivalent doses of analgesics. Equianalgesic charts are used for calculation of an equivalent dose between different analgesics. Tables of this general type are also available for NSAIDs, benzodiazepines, depressants, stimulants, anticholinergics and others.
An opiate is an alkaloid substance derived from opium. It differs from the similar term opioid in that the latter is used to designate all substances, both natural and synthetic, that bind to opioid receptors in the brain. Opiates are alkaloid compounds naturally found in the opium poppy plant Papaver somniferum. The psychoactive compounds found in the opium plant include morphine, codeine, and thebaine. Opiates have long been used for a variety of medical conditions, with evidence of opiate trade and use for pain relief as early as the eighth century AD. Most opiates are considered drugs with moderate to high abuse potential and are listed on various "Substance-Control Schedules" under the Uniform Controlled Substances Act of the United States of America.
Morphine-N-oxide (genomorphine) is an active opioid metabolite of morphine. Morphine itself, in trials with rats, is 11–22 times more potent than morphine-N-oxide subcutaneously and 39–89 times more potent intraperitoneally. However, pretreatment with amiphenazole or tacrine increases the potency of morphine-N-oxide in relation to morphine. A possible explanation is that morphine-N-oxide is rapidly inactivated in the liver and impairment of inactivation processes or enzymes increases functionality.
